Safety switch



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Patented Oct. 16, 1928.

ANDREW E. GRISWOLD, OF SEATTLE, WASHINGTON.

SAFETY SWITCH.

Application filed December 27, 1926. Serial No. 157,155

This invention relates to improvements to safety switches of that type contained in boxes and actuated by an exterior lever; more particularly, the invention relates to a quick break construction for switches of that type illustrated and described in my pending application for patent on safety switch, tiled August 25, 1923, under Serial Number 659,280.

The principal object of this invention is to provide a compression spring in the connection between the switch blades and the actuating lever whereby they are moved froml on to oit position, which acts to make a quick break.

Other objects of the invention reside in the various details of construction and cornbination of parts as is hereinafter described.

ln accomplishing these and other objects of the invention. I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Figure 1 is a central, vertical section of a safety switch embodying a quick break construction in accordance with the present invention.

Figure 2 is a horizontal section taken substantially on the line 2 2 in Figure 1. Figure 3 is a perspective view illustrating the switch blade mounting bars and the compression spring in the connection with the actuating link. v

Figure 4 is a detail perspective view' of parts of the switch bars and blades.

Referring more in detail to the drawings- 1 designates the switch box, or housing, wherein the switch mechanism proper is contained. The box preferably is of rectangular form and of sheet metal construction and is provided at the front with an upwardly swinging, hingedly mounted door 2 that gives access to the interior of the box. A

lock, as designated at 3, may be provided toV hold the door closed.

4 designates the switch panel. This is made ot slate, ebony, asbestos or other suit able insulating material and is iixed to the back wall within the housing by any suitable means, such as the bolts 5, which extend through the panel and wall and have nuts 6 tightened on their outer ends.

Fastened to the upper edge portion of the panel by bolts 7, are terminals 8, which have electrical connection by means of plates 9 with switch jaws 10 that are fastened to the panel by b olts 11. These switch jaws are vertlcally alined with. corresponding` sets of jaws 12 secured to the panel by bolts 13 and connected respectively by straps 14 with fuse clips 15 fastened to the panel by bolts 16. Fuses 17 connect the clips 15 with other clips 18 that are alined therewith and which arc fixed to the panel by bolts 19, and which are connected by straps 2O with terminals 21 secured byv bolts 22.

Fixed in the panel near its upper end and extending in parallel relation therefrom and in the same horizontal plane, are posts 24 24 andy slidably mounted thereon is a switch bar comprising two spaced apart bars 26-27 ot insulating material.. such as hard rubber or libre, and between which the switch blades 28 are rigidly clamped. These blades are adapted to be moved, by shitting of the switch bar along the posts, into and from the paired jaws 10 and 12 to make and break the electrical connection between the upper and lower terminals 8 and 21.

' The two bars 2G and 27 are transversely grooved as at 30 in Figure 4, to receive the edges of the switch blades and the blades also are notched as at 31 to receive the bars so that they cannot become displaced relative to cach other, and the bars are clamped against the blades and the whole structure held rigid by thimbles, or sleeves, 35 through which the posts slide and which at their ends extend through the bars and are crimped outwardly, as at 36, so as to be securely fixed therein.

The means provided for shitting the switch bar comprises a handle or lever that is pivotally mounted at its lower end by means of a pivot pin 41 within a bracket 42 fixed to the outside of the front wall of the housing. This handle is connected pivotally, as at 43, with the outer end of a link 44 which extends through a slot 45 in the housing wall and at its inner end is slidable through a. slot 46 in a yoke 47 that is fixed to the bar; the yoke having out-turned ends 47 through which the outer ends of the thimbles extend and are clinched to thereby rigidly mount the yoke. At the inner end of the link is a cross plate 48 and coiled about the link, between the cross plate 48 and yoke, is a compression spring 50 which provides a yielding connection.

When it is desired to close the switch, the lever 4() is shifted inwardly, from the full line position as shown in Figure 1 to the dotted line position. By this shifting the inner end of link 44; is caused to engage the cross bar 27 and the whole switch bar unit. to be shifted bodily inward along posts 24.24 to cause the switch blades to be moved into the switch jaws l() and 12. When' it is desired to open the switch, the lever 40 is pulled outwardly but with its initial 'movement there will be no shifting of the switch bar because of the yieldable connection provided by the spring 50 and the holding or gripping pressure of the jaws against the switch blades. However, as soon as the spring has been compressed, the bar will be moved outwardly toward H position and the spring acts, just as soon as the holding pressure of the jaws is overcome, to snap the bar outwardly to its limit of travel to make a quick break. rlhis is possible whether or not the lever is at its outer limit, since there is no iixed connection between the yoke i7 and the link 44e.

An additional insulating plate, 55, overlies the outer face of bar 27 beneath the yoke end 4T and its edges extend somewhat beyond the upper and lower edges ot' the bar.

In order that the parts inside the housing may not be reached except at times when the switch is off, l have provided the lever 40 with a leg 6() extended beyond the pivot point and which is adapted when the switch is closed to engage with a stopv lug 6l ixed to the outer face of the door 2 in such position that the door cannot be opened except when the switch lever is in ol' position.

Having thus described my invention, what l claim as new therein and desire to. secure by Letters-Patent, is: i

l. ln a switch 'of the character described, a mounting panel, switch jaws mounted on said panel and adapted for connection with line terminals, a slidably mounted switch bar, blades mounted by said bar and movable therewith into and from the jaws, a switch meegaan actuating lever, a link connected at one end with the lever and having a lost motion connection with the bar and a compression spring providing connection between the link and vbar andl which is placed under compression by an opening movement of the lever and which, by expansion, eiiects a quick break as the blades are released from the jaws.

2. In a switch of the character described, a mounting panel, switch jaws mounted on the panel and adapted for connection with line terminals, a pair of posts fixed on the panel, a switch bar slidable on said posts, blades mounted in the bar and adapted to be moved thereby into and from the jaws, a yoke fixed to the bars having a slot therein, andan actuating means for the bar including a link that has one end slidable through said slot, a cross plate fixed to the said end ot the link and a spring disposed between the said plate and yoke which is placed under compression by an openingmovement otl the link and which, by expansion, eiiects a quick break as the blades leave the jaws.

In a switch of the character described, a housing, a mounting panel within the housing, switch jaws mounted on the panel adapted for connection with line terminals, a pair ot posts fixed on the panel, a switch bar slidably mounted on the posts, switch blades mounted by the bar and movable therewith into and from the jaws, a yoke fixed to the bar having a slot therein, a lever pivotally mounted on the housing'A` a link pivotally connected at one end with the lever` and slidable at its 'other end through the yoke slot, a cross plate fixed to the latter end of the link and a coiled compression spring disposed about the link between the yoke and said end plate.

Signed at Seattle, llVasnington, this 26th day of November, 1926.

ANDREW? IE. GHlSVVOLD. 

